Patent GB-561408-A (GB)
Title: Improved heat-treating apparatus
IPC: C21D1/74
Filed: 1943-01-04
Abstract: 561,408. Electric furnaces. WESTERN ELECTRIC CO., Inc. Jan. 4, 1943, No. 126. Convention date, Jan. 10, 1942. [Class 39 (iii)] [Also in Group XII] Apparatus for the heat treatment of materials comprises a furnace having its heating-chamber closed to the entry of external air and communicating with a cooling-chamber also capable of closure to entry of air and provided with a charging door, a quenching tank, a movable carrier for transferring articles between the heating and cooling chambers and quenching tank and means for supplying a prepared atmosphere such as nitrogen to the heating and cooling chambers. As shown in Figs. 2 and 3, the heating-chamber 75 is enclosed at the sides by refractory members 76 which are cut away at their sides and ends to receive an electric heating coil 78 which is formed into several folds at the top and bottom of the heating-chamber so that these parts which are not heavily insulated may receive more heat. Goods to be treated are supported on a perforated platform 96 suspended from a chain 84 passing through an aperture 83 in a cover 82 and into a closed casing 90 where it is suspended from a pulley 85 driven by a motor 87. After heat treatment, the goods are lowered through sliding doors 56, 57 operated by right- and left-handed screws into a waterjacketed cooling-chamber 19 and thence into a quenching tank 12. The cooling-chamber 19 is provided with a water-jacketed door 30, having a window 45, for the insertion and removal of the articles to be treated. The heattreatment atmosphere enters the apparatus by a pipe 92 in the casing 90 and flows through the heating-chamber through a passage 100 in the doors 56, 57 into the cooling-chamber and leaves by a pipe 101. The Specification as open to inspection under Sect. 91 describes also plants for the manufacture of nitrogen to be used in the furnace. As shown in Fig. 5 (Cancelled), a pump 102 draws air from the atmosphere through a pipe 103 or nitrogen gases which have been circulated through the furnace through a pipe 101 and forces it through drying chambers 110, 112 alternately according to the position of the valves 109, 116. The drying-chambers have heating elements 111, 113. The dried air passes through a pipe 117 to one or the other of the heated retort chambers 121, 122 containing copper wire, according to the position of valves 120, 130, the oxygen is removed and the nitrogen produced passes to the furnace 75 through pipe 92. Reduction of the oxidised copper is effected in the retort chamber which is not being used for the production of nitrogen by passing reducing gases through it from a heated retort 131 through which natural gas and air are passed, the hydrogen and carbon monoxide so obtained being led through the pipe 136 to the retort chamber. Another form of nitrogen plant is shown in Fig. 6 (Cancelled). Air from the atmosphere or nitrogen gases from the furnace supplied by pipes 103, 101 are fed by a pump 147 to a retort 141 filled with iron chips and thence to a retort 140 filled with charcoal both retorts being heated externally by elements 144. The gas leaving the retort 140 consists of nitrogen with small amounts of hydrogen and carbon monoxide. Such gas is led to the furnace 75 through pipe 92 and by operating valve 150 to connect the pipe 149 to the pipe 151 and by closing the valve 145 the pump may circulate the gas from the retort 140 over the oxidised iron on the retort 141 for reducing purposes. This subject-matter does not appear in the Specification as accepted.